Dooeui,

ETFS does not perform static wear leveling of /dev/etfs1.  The reason is
that ETFS cannot know the format of the data stored there, so it does
not risk moving data.

In 6.4.1, etfsctl and ETFS support specifying an offset when erasing and
reading/writing to /dev/etfs1.  For earlier versions, I recommend simply
using "cat" to combine each of the IPL and IFS, and then etfsctl -w to
write the combined file to /dev/etfs1.

The read-disturb behaviour of NAND is unfortunate, because it can cause
many problems for boards which boot from NAND.  Some good ways to reduce
this risk are to use SLC NAND, which has much better read-disturb
reliability, and to store two copies of the IFS.  The IPL then boots the
first one, unless it is corrupted.  If the second one is booted, then it
takes an extra action to refresh the first IFS.

Regards,

David 

> -----Original Message-----
> From: Dooeui Hong [mailto:community-noreply@qnx.com] 
> Sent: February 27, 2010 7:30 AM
> To: general-filesystems
> Subject: Static wear-leveling for IPL or IFS on NAND
> 
> Dear QNX, 
> 
> 1. How ETFS handle static wear-leveling for raw 
> partition(/dev/etfs1) ?
> 2. If system has only NAND flash and use it for boot device, 
> should /dev/etfs1 has both IPL and IFS ?  I means, should  
> image.ifs has both IPL and IFS ?
> 
>    etfsctl -d /dev/etfs1 -e -w image.ifs
> 
> I cound't find an option which specify "offset".
> Please let me know if there is any way to write IPL and IFS 
> on ETFS seperately.
> 
> 3. If ETFS won't support static wear-leveling for /dev/etfs1, 
> Can I  install 2 IPL and 2 IFS on /dev/etfs1 ?  Could you let 
> me know how can I do this ?
> 
> For example, If there is any new bad block on ifs1, I'd like 
> to read IFS from ifs2. 
> 
> Thanks,
> Dooeui
> 
> 
> 
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